Emergency Medical Services. Группа авторов
intervention for appropriate patients. Sedation with a benzodiazepine before countershock may improve patient comfort. However, countershock should not be delayed for unstable patients while awaiting clinical sedation.
Pediatric dysrhythmias
Children under the age of 5 years can sustain a sinus tachycardia at much higher rates (up to 225/minute) in response to physiological stresses. Look for hypovolemia, hypercarbia, and hypoxemia in stable children with narrow‐complex tachydysrhythmia before drug therapy is used. A volume challenge with 10 to 20 mL/kg of Ringer’s solution or another isotonic fluid IV is often useful before other therapies.
Figure 10.1 The classic one‐lead ECG appearance (lead II here) of torsades de pointes.
Note the shifting of the QRS complex axis and appearance.
Some guidelines make a distinction between energy levels when performing synchronized versus unsynchronized countershock. To keep treatments simple but effective, unstable children deserve countershock with 2 J/kg. Antidysrhythmic principles are otherwise like those outlined previously, with agents given in the appropriate weight‐based doses. Pediatric noncardiac arrest bradycardias are also usually secondary to another cause, often respiratory distress or hypoxia. When symptomatic, treat these rhythms primarily with epinephrine and airway maneuvers. There is rarely a need for transcutaneous pacing or atropine (0.02 mg/kg/dose).
Torsades de pointes
This rare dysrhythmia classically presents with paroxysms of syncope and polymorphic “twisting” of the QRS complexes (Figure 10.1). Torsades de pointes (TdP) in adults is usually “pause dependent,” flourishing when the intrinsic heart rate drops below 80 to 100/minute. A variety of antidysrhythmics (essentially all, aside from lidocaine and calcium channel or beta‐adrenergic blocking agents), antihistamines, antimicrobials, and psychoactive drugs, along with metabolic disorders, can precipitate TdP in adults. Field treatment consists of countershock when unstable and transcutaneous pacing or isoproterenol (titrated to a heart rate >120/minute). Magnesium sulfate, 2 g as a rapid IV bolus, is also suggested for those who fail countershock. In children, TdP is rare, inherited, and treated with slowing heart rate.
A more practical problem is mistaking VT or VF for TdP. VT and VF often display some changes in QRS complex appearance. EMS clinicians may mistake these variations for the classic, but rare, QRS twisting. If recurrent polymorphic VT occurs in a patient with one or more of the aforementioned risks, treatment should be started. Otherwise, orders and protocols should focus on the treatment of common VT.
Rhythm disturbances in renal failure patients
This group is often affected by metabolic derangements that alter rhythms, in addition to having high rates of underlying heart disease. Hyperkalemia is a common complication of renal failure that can cause a bradycardia or a wide‐complex rhythm, although the latter is usually not above a rate of 100 to 120/minute and often much slower. Treatment should include IV calcium, high‐dose nebulized albuterol, and insulin plus glucose. Albuterol rapidly (but temporarily) shifts potassium into the cells and should be part of protocols for any renal failure patient with new‐onset symptomatic bradycardia or a wide‐complex rhythm. Insulin and glucose also work quickly, but insulin is rarely available in the field. If used, however, insulin and glucose infusions are best done with direct medical oversight supervision due to the risk of hypoglycemia.
| Mode | Planning factor | Distance | Limiting factor | Notes |
| Ambulances (ground) Type I – ALS non‐HAZMAT Type II – BLS non‐HAZMAT Type III – Bariatric ALS, non‐ HAZMAT Type IV – ALS/critical care transport, non‐HAZMAT | One critical or two stable patients per ambulance | Good for short or intermediate distances no more than 250 miles. | Oxygen Road conditions | Evacuation of hospital patients may require care that exceeds most paramedic training |
| Paratransit vehicles Type I – Sedan/minivan (1‐7 seats) Type II – Minibus (8‐26 seats) Type III – transit bus (>26 seats) Type IV – Wheelchair van (1‐9 seats with wheelchair lift) Type V – ADA minibus (10‐26 seats with wheelchair lift) Type VI – ADA transit bus | Determine the seat requirement. The contractor determines the number of vehicles required based on seat requirements. | Good for short or intermediate distances for wheelchair patients | Road conditions IAW FEMA contract, the one‐way distance to transport paratransit passengers shall not exceed 250 miles | Paratransit transportation means comparable transportation services required by the Americans with Disabilities Act A for people with disabilities who are unable to use fixed route transportation systems. |
| Commercial air ambulances (rotary) Type 1 – Critical care and ALS, 2 or more litter patients Type 2 – Critical care and ALS, 1 litter patient Type 3 – Neonatal specific | Depends on the model of aircraft, but assume one litter for planning purposes. | Rotor‐wing for medical facilities to medical facilities or from medical facility to airport of embarkation (APOE) Good for short and intermediate distances but for planning purposes no more than 150 miles. The goal is to be able to deliver the patients quickly and return to provide additional lifts as needed | Experience and qualification of medical crew. Equipment onboard Oxygen Weather conditions Crew rest: Usually 10 hours in a 24‐hour period. | All air ambulances will have at least three crewmembers (pilot and two medical attendants) |
| Commercial air ambulances (fixed wing) Type 1 – Critical care and ALS, 2 or more litter patients Type 2 – Critical care and ALS, 1 litter patient Type 3 – Neonatal specific | Depends on the model of aircraft, but assume no more than two litters for planning purposes. | Good for intermediate and long distances, but for planning purposes no more than 150 miles. The goal is to be able and deliver the patients quickly and return to provide additional lifts as needed | Experience and qualification of medical crew. Equipment onboard Oxygen Weather conditions Crew rest: Usually 10 hours in a 24‐hour period. | All air ambulances will have at least three crewmembers (pilot and two medical attendants) |
NOTE: Type refers to FEMA’s methods for the categorization and description of resources that are commonly exchanged in disasters via mutual aid, by capacity and/or capability.
Source: Based on FEMA Resource Typing Library Tool v1.5.3. Available at: https://rtlt.preptoolkit.fema.gov/Public/Combined
Lidocaine can cause asystole in the presence of hyperkalemia. The role of other agents, including amiodarone, is unknown in the rare event of hyperkalemia and new‐onset wide‐complex tachydysrhythmia [14]. If a rhythm‐specific intervention is needed in unstable patients with suspected hyperkalemia, electricity (pacing for slow, countershock for fast rates) is a safe choice.
Protocols
When developing protocols,